背景:桡骨远端C1型骨折属于关节内不稳定型骨折,治疗上存在较大的难度.目前对桡骨远端骨折不同内固定接骨板的临床研究较少,缺乏多种内固定接骨板的生物力学对比研究,在内固定接骨板的选用上仍存在争议.目的:通过有限元分析法比较不同内固定接骨板在桡骨远端C1型骨折治疗中的生物力学特性.方法:使用一名健康女性志愿者的桡骨模型,顺序导入Mimics 21.0、Geomagic Wrap 2017、Solid Works 2021等软件进行处理,制作桡骨远端C1型骨折模型.根据厂家提供的接骨板数据,分别建立桡骨远端掌侧斜T形锁定板、桡骨远端掌侧蝶形锁定板、桡骨远端掌侧万向锁定板和螺钉的三维模型,并且和骨折模型进行装配,在ANSYS 19.0中赋予材料属性,设定各接触面相互作用关系并定义载荷及边界条件,模拟其腕关节压缩、背弯、掌屈和扭转等4种载荷工况,比较其生物力学性能.结果与结论:①3组内固定模型在4种载荷工况下,内固定模型整体位移主要集中在桡骨远端关节面上;模型在背弯、掌屈和扭转载荷工况下的最大位移是轴向载荷下位移的2-6倍,表明轴向载荷工况下内固定系统最稳定;②内固定上的应力远大于骨折块上的应力,内固定物应力主要集中于接骨板在骨折断端附近区域,其中万向锁定板和蝶形锁定板应力分布较为均匀,斜T形锁定板应力集中现象最为明显;③在压缩和扭转载荷下,骨折块的应力主要集中在螺钉孔周围,掌屈和背伸载荷下则是从桡骨远端向近端逐步扩展;在同样的载荷工况下,斜T形锁定板固定状态下骨折块应力最大,万向锁定板固定系统骨折块所受应力峰值最低,蝶形锁定板与万向锁定板固定状态下的骨折块峰值应力仅仅相差0.2-6.0 MPa;④相比于斜T形锁定板和蝶形锁定板,万向锁定板在桡骨远端C1型骨折内固定中应力分布更均匀,固定模型关节面位移更小、稳定性更佳.
Finite element analysis of three internal fixation plates for treating C1 type fractures of distal radius
BACKGROUND:The C1 type fracture of the distal radius is an intraarticular unstable fracture,which is difficult to treat.At present,there are few clinical studies about the comparison of the biomechanical differences of different internal fixation plates for distal radius fractures under different loading conditions,and there are still controversies in the selection of internal fixation plates.OBJECTIVE:To compare the biomechanical properties of different internal fixation plates for C1 type fractures of distal radius using a finite element analysis method.METHODS:The distal radius model of a healthy female volunteer was used,and the files were sequentially imported into Mimics 21.0,Geomagic Wrap 2017,and Solid Works 2021 for processing.The C1 type fracture of the distal radius was modeled.According to the plate data provided by the manufacturer,the volar oblique T-locking plate,volar fixed-angle anatomical plate,volar variable-angle locking plate and screws three-dimensional model were created and assembled with the fracture model.The material properties were given in ANSYS 19.0 to set up the relationship of interaction between the contact surfaces,and to define the loads and boundary conditions.Four load cases,including compression,dorsal flexion,palmar flexion and torsion,were applied to compare the biomechanical properties.RESULTS AND CONCLUSION:(1)In the three groups of internal fixation models,the overall displacement of the internal fixation model was mainly concentrated on the articular surface of the distal radius under four load conditions.The maximum displacement of the model under the dorsal,palmar and torsion load conditions was 2-6 times that of the displacement under the axial load,indicating that the internal fixation system was the most stable under the axial load condition.(2)The stress on the internal fixation was much greater than the stress on the bone fracture fragments.The stress of the internal fixation was mainly concentrated in the area that near to the fracture end of the bone plate,among which the stress distribution of the volar fixed-angle anatomical plate,volar variable-angle locking plate was relatively uniform,and the stress concentration of the oblique T-locking plate was the most obvious.(3)Under compressive and torsional loads,the stress of the fracture fragments was mainly concentrated in the area that around the screw holes.Under dorsal and palmar flexion,it gradually expanded from the distal end to the proximal radius.Under the same load condition,the stress of the fracture block in the oblique T-locking plate fixation state was the highest,and the peak stress of the fracture fragments in the volar variable-angle locking plate fixation system was the lowest.The difference between the peak stress of the bone fracture fragments in the fixed state of the volar fixed-angle anatomical plate and the volar variable-angle locking plate was only in the range of 0.2-6.0 MPa.(4)It is indicated that compared with the oblique T-locking plate and the volar fixed-angle anatomical plate,the volar variable-angle locking plate has more uniform stress distribution,less displacement of articular surface,and the best stability in the internal fixation in the C1 type fracture of the distal radius.
万方数据
维普
